1. Field of the Invention
The invention relates to a steering system.
2. Discussion of Background
A steering system has been proposed in which a steering angle sensor that detects a steering angle is fitted to a lower end of a steering column (for example, WO 2005/005231A1). A lower end of a column shaft, which projects from the lower end of the steering column, is connected to an intermediate shaft via a universal joint.
Typically, a column shaft is provided with a width-across-flat forming portion that serves as a sensor fitting portion to which a rotor of a steering angle sensor is fitted, and a male serration forming portion that serves as a universal joint yoke fitting portion to which a yoke of a universal joint is fitted. However, in the column shaft, outer diameters of the width-across-flat forming portion and the male serration forming portion are different from each other, and machining manners for the width-across-flat forming portion and the male serration forming portion are different from each other. Therefore, a tapered portion for connecting the width-across-flat forming portion with the male serration forming portion, and a relief portion for machining are provided between the width-across-flat forming portion and the male serration forming portion. Thus, there has been a problem that an entire length of machined portions including the tapered portion and the relief portion is increased in an axial direction of the column shaft.